Werner Herzog's 2005 portrait of Timothy Treadwell, who lived with grizzly bears until one ate him. The Herzog doc most quoted by Herzog impressionists.
From Wikipedia
Grizzly Man is a 2005 American documentary film written and directed by Werner Herzog. It chronicles the life and death of bear enthusiast and conservationist Timothy Treadwell and his girlfriend Amie Huguenard at Katmai National Park, Alaska. The film includes some of Treadwell's own footage of his interactions with brown bears before 2003, and of interviews with people who knew or were involved with Treadwell, in addition to professionals who deal with wild bears.